Microchip Electrophoretic Immunoassay for Serum Cortisol

Abstract

An immunoassay performed using a microchip electrophoretic system is described. Separation and quantitation of free and bound labeled antigen in a competitive assay are carried out in channels micromachined into fused silica substrates. Such microchips are attractive because of their small size, ruggedness, and amenability to automated handling. The assay achieves the determination of cortisol in blood serum over the range of clinical interest (1-60 micrograms/dL) without the need for extraction or other sample preparation steps. The separation is performed in less than 30 s. Very high throughput is possible by operating the assay in multiple channels in parallel. These characteristics make microchip electrophoretic systems a promising technology for the rapid analysis of clinical samples.

Magnetic bead handling on-chip: new opportunities for analytical applications

“…Immuno-assays are probably the most important analysis method for biological molecules, as the molecular recognition reaction provides high selectivity and chemical sensitivity. Although conventional microtiter plate assays continue to play an important role, enzyme assays, DNA binding, and competitive immuno-assays have been performed on microdevices (Koutny et al 1996;Chiem and Harrison 1997;Hadd et al 1997). The three cited experiments were homogeneous immuno-assays in which both the antigen and the antibody molecules are simultaneously introduced in a solution, complexation takes place, and an electrophoretic separation and detection follows.…”

New advances in microchip fabrication for electrochromatography

“…Structures on glass substrate are most commonly generated by standard photolithographic techniques. The basic manufacturing steps are the same as for silicon except the Cr/Au protective layer (the mask) representing a significant difference usually applied for glass [13,[22][23][24][25], where chrome is applied to enhance the adhesion of gold to the glass surface. Gold was found to be an efficient protective material for most glass-etching materials.…”

Integration of a Nanoporous Platinum Thin Film into a Microfluidic System for Non-enzymatic Electrochemical Glucose Sensing

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